Ketamine as a rapid-acting agent for suicidal ideation: A meta-analysis

Efficacy of single and repeated ketamine administration for suicidal ideation in adults with psychiatric disorders: A meta-analysis

BACKGROUND

Previous studies have demonstrated rapid-onset anti-suicidal ideation effects of ketamine. This study aimed to compare the efficacy and duration of anti-suicidal thoughts following single- and repeated-dose ketamine administration.

METHODS

We retrieved published studies on ketamine for suicidal ideation (SI) from PubMed, OVID (MEDLINE), Web of Science, and Embase, spanning from inception to May 1, 2024. Standardized mean differences (SMD) in the SI scores were calculated for continuous outcomes.

RESULTS

This study included 49 independent clinical trials involving 3982 participants. After a single ketamine administration, a significant reduction in SI was observed at 4 h (SMD = -0.607, 95 % confidence interval (CI) = [-0.797, -0.418], I2 = 40.69 %), with peak effects observed at 24 h (SMD = -0.955, 95 % CI = [-1.229, -0.682], I2 = 63.66 %) and effects persisted for one month (SMD = -0.948, 95 % CI = [-1.611, -0.285], I2 = 74.32 %). Similar anti-suicidal effects were observed at the treatment endpoint (SMD = -1.228, 95 % CI = [-1.506, -0.950], I2 = 94.56 %) and during a follow-up period of greater than or equal to 1 week (SMD = -1.012, 95 % CI = [-1.695, -0.330], I2 = 80.44 %) with multiple doses of ketamine administration.

CONCLUSIONS

Single ketamine treatment may have a significant and lasting (up to 1 month) beneficial effect on SI. There was no statistical difference in efficacy between single and serial ketamine administration, and less durability was found in serial ketamine treatment.

Patient-derived induced pluripotent stem cells: Tools to advance the understanding and drug discovery in Major Depressive Disorder

Major Depressive Disorder (MDD) is a pleomorphic disease with substantial patterns of symptoms and severity with mensurable deficits in several associated domains. The broad spectrum of phenotypes observed in patients diagnosed with depressive disorders is the reflection of a very complex disease where clusters of biological and external factors (e.g., response/processing of life events, intrapsychic factors) converge and mediate pathogenesis, clinical presentation/phenotypes and trajectory. Patient-derived induced pluripotent stem cells (iPSCs) enable their differentiation into specialised cell types in the central nervous system to explore the pathophysiological substrates of MDD. These models may complement animal models to advance drug discovery and identify therapeutic approaches, such as cell therapy, drug repurposing, and elucidation of drug metabolism, toxicity, and mechanisms of action at the molecular/cellular level, to pave the way for precision psychiatry. Despite the remarkable scientific and clinical progress made over the last few decades, the disease is still poorly understood, the incidence and prevalence continue to increase, and more research is needed to meet clinical demands. This review aims to summarise and provide a critical overview of the research conducted thus far using patient-derived iPSCs for the modelling of psychiatric disorders, with a particular emphasis on MDD.

Ketamine Infusion in a Resistant Obsessive-Compulsive Disorder Patient in Bangladesh with Severe Suicidal Ideation: A Case Report

Treatment of resistant obsessive-compulsive disorder (OCD) typically results in insufficient symptom alleviation, and even long-term medication often fails to have the intended effect. Ketamine is a potent non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor. Studies have shown that low-dose ketamine infusion results in a considerable reduction in obsessive-compulsive symptoms and a rapid resolution of suicidal ideation. This is a case report on the effect of intravenous ketamine infusion on a patient with resistant OCD and severe suicidal ideation. Intravenous (IV) ketamine was given once a week over consecutive three weeks with necessary precautions. Psychometric tools such as the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), the Clinical Global Impressions Scale (CGI-S), the Beck Scale for Suicidal Ideations (BSSI), and Depression Anxiety and Stress Scale 21 (DASS-21) were applied before and after infusions. Obsessive-compulsive symptoms and suicidal severity started to decrease rapidly after the first infusion. However, after a transient improvement, these symptoms again began to increase after a stressful incident on the second day of the first infusion. All the symptoms measured by validated rating scales showed continued improvement after the following two infusions. The improvement was sustained until discharge (one week after the last infusion) and subsequent follow-up in the sixth and 12th weeks. The role of ketamine in reducing suicidal thoughts and behavior is already established. Very few studies emphasized its effectiveness in improving severe/resistant obsessive-compulsive symptoms. This pioneering work may offer scope for similar research in the relevant field.

Antidepressant mechanisms of ketamine's action: NF-κB in the spotlight

Ketamine recently approved for therapy of treatment-resistant depression shows a complex and not fully understood mechanism of action. Apart from its classical glutamatergic N-methyl-D-aspartate receptor antagonistic action, it is thought that anti-inflammatory properties of the drug are of clinical relevance due to the contribution of activated inflammatory mediators to the pathophysiology of depression and non-responsiveness of a group of patients to current antidepressant therapies. In a search of the mechanism underlying anti-inflammatory effects of ketamine, the nuclear factor kappa B transcription factor (NF-κB) has been proposed as a target for ketamine. The NF-κB forms precisely regulated protein signaling cascades enabling a rapid response to cellular stimuli. In the central nervous systems, NF-κB signaling appears to have pleiotropic but double-edged functions: on the one hand it participates in the regulation of processes that are crucial in the treatment of depression, such as neuroplasticity, neurogenesis or neuronal survival, on the other - in the activation of neuroinflammation and cell death. Ketamine has been found to reduce inflammation mediated by NF-κB, leading to decreased level of pro-inflammatory cytokines and other inflammatory or stress mediators. Therefore, this review presents recent data on the significance of the NF-κB cascade in the mechanism of ketamine's action and its future perspectives in designing new strategies for the treatment of depression.

Suicidal Ideations in Major Depressed Subjects: Role of the Temporal Dynamics of Anhedonia

Given the limited data available in the literature, the aim of this study was to investigate the potential role played by the temporal dynamics of anhedonia (lifelong anhedonia and recent changes in anhedonia) in the occurrence of suicidal ideations in major depressed subjects. The clinical data of 285 major depressed subjects recruited from the database of the Erasme Hospital Sleep Laboratory were analyzed. A score on item nine of the Beck Depression Inventory (BDI-II) ≥1 and/or an identification during the systematic psychiatric assessment were used to determine the presence of suicidal ideations. The association between anhedonia complaints (lifelong anhedonia and recent change in anhedonia) and suicidal ideations in major depressed subjects was assessed by logistic regression analyzes. The prevalence of suicidal ideations was 39.3% in our sample of major depressed subjects. After adjusting for the main confounding factors, multivariate logistic regression analysis demonstrated that unlike lifelong anhedonia, only recent changes in anhedonia were a risk factor for suicidal ideations in major depressed subjects. Given this potential involvement of the recent change in anhedonia in the occurrence of suicidal ideations in major depressed subjects, it seems essential to better identify and adequately manage this specific form of anhedonia in order to open new perspectives for the prevention of suicide in this particular sub-population.

Ketamine Treatment for Alcohol Use Disorder: A Systematic Review

Alcohol use disorder (AUD) is a chronic, recurrent condition that demonstrates significant heterogeneity in treatment response to first-line agents. Ketamine may have a therapeutic role in substance use disorders; however, research on this topic is limited. The objective of this systematic review is to qualitatively synthesize the current evidence of ketamine treatment for alcohol use disorder and evaluate its efficacy. A systematic review of Medline, PsycINFO, CINAHL, the Cochrane Library, and Google Scholar was performed to identify completed human studies in English or Spanish (from inception to July 2022) that assess the effectiveness of ketamine therapy for alcohol use disorder. This review was registered on the Open Science Framework. Data were descriptively summarized and presented in tables and tested via narrative synthesis methodology. The risk of bias was measured with Cochrane Collaboration tools and a case series quality assessment tool. A total of 11 studies with 854 adult patients in three different countries (the USA, the UK, and Russia) were analyzed. Sample sizes ranged from 5 to 211 people. Seven studies included patients with alcohol use disorder, one study focused on heavy drinkers, and three studies elaborated extensively on alcohol withdrawal. The overall proportion of patients achieving abstinence and reduced consumption was most favorable in people receiving combination ketamine and psychotherapy treatment. The results were mixed with respect to relapse, craving, and withdrawal. Ketamine may be an effective therapeutic modality for people with alcohol use disorders who fail to respond to FDA-approved first-line agents. More robust clinical trials are necessary to provide a more accurate assessment of efficacy, safety profile, and dosing strategies for ketamine utilization in alcohol use disorder.

Changes in white matter microstructure following serial ketamine infusions in treatment resistant depression

Ketamine produces fast-acting antidepressant effects in treatment resistant depression (TRD). Though prior studies report ketamine-related changes in brain activity in TRD, understanding of ketamine's effect on white matter (WM) microstructure remains limited. We thus sought to examine WM neuroplasticity and associated clinical improvements following serial ketamine infusion (SKI) in TRD. TRD patients (N = 57, 49.12% female, mean age: 39.9) received four intravenous ketamine infusions (0.5 mg/kg) 2-3 days apart. Diffusion-weighted scans and clinical assessments (Hamilton Depression Rating Scale [HDRS-17]; Snaith Hamilton Pleasure Scale [SHAPS]) were collected at baseline and 24-h after SKI. WM measures including the neurite density index (NDI) and orientation dispersion index (ODI) from the neurite orientation dispersion and density imaging (NODDI) model, and fractional anisotropy (FA) from the diffusion tensor model were compared voxelwise pre- to post-SKI after using Tract-Based Spatial Statistics workflows to align WM tracts across subjects/time. Correlations between change in WM metrics and clinical measures were subsequently assessed. Following SKI, patients showed significant improvements in HDRS-17 (p-value = 1.8 E-17) and SHAPS (p-value = 1.97 E-10). NDI significantly decreased in occipitotemporal WM pathways (p < .05, FWER/TFCE corrected). ΔSHAPS significantly correlated with ΔNDI in the left internal capsule and left superior longitudinal fasciculus (r = -0.614, p-value = 6.24E-09). No significant changes in ODI or FA were observed. SKI leads to significant changes in the microstructural features of neurites within occipitotemporal tracts, and changes in neurite density within tracts connecting the basal ganglia, thalamus, and cortex relate to improvements in anhedonia. NODDI may be more sensitive for detecting ketamine-induced WM changes than DTI.

Molecular mechanisms underlying the N-methyl-d-aspartate receptor antagonists: Highlighting their potential for transdiagnostic therapeutics

The so-called "psychedelic renaissance" has stimulated expanded interest in several classes of drugs that appear to possess transdiagnostic effects in the treatment of mental health disorders, specifically. N-methyl-d-aspartate receptor (NMDAR) antagonists are one such class with diverse therapeutic potential. NMDARs mediate excitatory postsynaptic signalling in the central nervous system (CNS) and are integral to normal neurobiological processes including neuronal development, synaptic transmission, and plasticity, and thus involved in learning and memory. However, NMDAR hyper-function is also implicated in acute CNS trauma, neuropsychiatric and neurodegenerative disorders, as well as chronic pain. The complex structure of NMDARs permits several locations for therapeutic inhibition, making these receptors a potential target for multiple drugs which modulate them in different ways. NMDAR antagonists, which may be competitive, non-competitive, or uncompetitive, either block glutamate from binding the receptor or modulate the response to glutamate binding. Despite longstanding concerns about side effects of NMDAR antagonists, recent research suggests that, when appropriately used, these agents have favourable safety profiles. Furthermore, their fast-acting mechanism of action, resulting in rapid effects compared to other therapeutic agents, makes them a promising class of drugs that may yield effective therapeutics for multiple CNS disorders.

Review of Herbal Medicines for the Treatment of Depression

Depression, a mental illness that is receiving increasing attention, is caused by multiple factors and genes and adversely affects social life and health. Several hypotheses have been proposed to clarify the pathogenesis of depression, and various synthetic antidepressants have been introduced to treat patients with depression. However, these drugs are effective only in a proportion of patients and fail to achieve complete remission. Recently, herbal medicines have received much attention as alternative treatments for depression because of their fewer side effects and lower costs. In this review, we have mainly focused on the herbal medicines that have been proven in clinical studies (especially randomized controlled trials and preclinical studies) to have antidepressant effects; we also describe the potential mechanisms of the antidepressant effects of those herbal medicines; the cellular and animal model of depression; and the development of novel drug delivery systems for herbal antidepressants. Finally, we objectively elaborate on the challenges of using herbal medicines as antidepressants and describe the benefits, adverse effects, and toxicity of these medicines.

(Es)Ketamine for Suicidal Ideation and Behavior: Clinical Efficacy

Suicidal ideation and behavior are among the most severe psychiatric presentations, warranting emergency room visits and psychiatric admission for higher levels of care. In the United States, suicide rates continue to climb, especially in younger patients, and the continued psychosocial stressors of the COVID-19 pandemic may further exacerbate this crisis. Suicidal ideation and behavior are core features of a major depressive episode, but there are limited treatment options to rapidly redress these life-threatening symptoms. Racemic ketamine and its S-enantiomer, esketamine, are N-methyl-D-aspartate receptor antagonists and glutamate modulators that have robust antidepressant efficacy in treatment-resistant major depressive disorder and bipolar depression. Additionally, both ketamine and esketamine have demonstrated rapid-acting antisuicidal efficacy in major mood disorders. In August 2020, this culminated in a first-in-class approval of Spravato® (intranasal esketamine) for the treatment of major depressive disorder with acute suicidal ideation and behavior. In this article, we review the literature in support of the antisuicidal efficacy of ketamine and esketamine.

New investigational agents for the treatment of major depressive disorder

INTRODUCTION

Pharmacotherapy of depression is characterized by the delayed onset of action, chronic treatment requirements, and insufficient effectiveness. Ketamine, with its rapid action and long-lasting effects, represents a breakthrough in the modern pharmacotherapy of depression.

AREAS COVERED

: The current review summarizes the latest findings on the mechanism of the antidepressant action of ketamine and its enantiomers and metabolites. Furthermore, the antidepressant potential of psychedelics, non-hallucinogenic serotonergic modulators and metabotropic glutamate receptor ligands was discussed.

EXPERT OPINION

Recent data indicated that to achieve fast and long-acting antidepressant-like effects, compounds must induce durable effects on the architecture and density of dendritic spines in brain regions engaged in mood regulation. Such mechanisms underlie the actions of ketamine and psychedelics. These compounds trigger hallucinations; however, it is thought that these effects might be essential for their antidepressant action. Behavioral studies with serotonergic modulators affecting 5-HT1A (biased agonists), 5-HT4 (agonists), and 5-HT-7 (antagonists) receptors exert rapid antidepressant-like activity, but they seem to be devoid of this effects. Another way to avoid psychomimetic effects and achieve the desired rapid antidepressant-like effects is combined therapy. In this respect, ligands of metabotropic receptors show some potential.

Arketamine, a new rapid-acting antidepressant: A historical review and future directions

The N-methyl-d-aspartate receptor (NMDAR) antagonist (R,S)-ketamine causes rapid onset and sustained antidepressant actions in treatment-resistant patients with major depressive disorder (MDD) and other psychiatric disorders, such as bipolar disorder and post-traumatic stress disorder. (R,S)-ketamine is a racemic mixture consisting of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine), with (S)-enantiomer having greater affinity for the NMDAR. In 2019, an esketamine nasal spray by Johnson & Johnson was approved in the USA and Europe for treatment-resistant depression. In contrast, an increasing number of preclinical studies show that arketamine has greater potency and longer-lasting antidepressant-like effects than esketamine in rodents, despite the lower binding affinity of arketamine for the NMDAR. Importantly, the side effects, i.e., psychotomimetic and dissociative effects and abuse liability, of arketamine are less than those of (R,S)-ketamine and esketamine in animals and humans. An open-label study demonstrated the rapid and sustained antidepressant effects of arketamine in treatment-resistant patients with MDD. A phase 2 clinical trial of arketamine in treatment-resistant patients with MDD is underway. This study was designed to review the brief history of the novel antidepressant arketamine, the molecular mechanisms underlying its antidepressant actions, and future directions.

Ketamine for suicidality: an umbrella review

The urgent need for appropriate treatment for suicide, the tenth leading cause of death, has led to numerous studies. This study aims to systematically identify and appraise systematic reviews with or without meta-analyses investigating ketamine in suicidal ideation and behaviors. The study protocol was published in PROSPERO (CRD42021285320). Scopus, ISI, Embase, PubMed, CINAHL, PsycINFO, Cochrane Library, Google Scholar, and two registries were searched on October 29 without any restrictions for systematic reviews investigating the efficacy of ketamine on suicidal ideation and behaviors. The primary outcome was the final inference of ketamine effectiveness. A formal narrative synthesis was conducted, and the AMSTAR-2 tool was used to evaluate the quality of the studies. No funding was received. Of 27 studies that addressed ketamine for suicidal ideation, only four reported mixed or negative results, and out of nine reviews, esketamine was significantly beneficial only in five. A transient rise in pulse rate and blood pressure, dissociation, confusion, blurred vision, nausea, and vertigo were of the most common adverse effects; however, most were mild. More than two-thirds of the included studies qualified as low or critically low quality. Preliminary evidence for the short-term efficacy of ketamine in suicidality was noted by the majority of reviews; however, long-term effects remained unknown. Due to the non-high quality of many studies and the limitations of core studies, further studies are required.

The Importance of Endoplasmic Reticulum Stress as a Novel Antidepressant Drug Target and Its Potential Impact on CNS Disorders

Many central nervous system (CNS) diseases, including major depressive disorder (MDD), are underpinned by the unfolded protein response (UPR) activated under endoplasmic reticulum (ER) stress. New, more efficient, therapeutic options for MDD are needed to avoid adverse effects and drug resistance. Therefore, the aim of the work was to determine whether UPR signalling pathway activation in astrocytes may serve as a novel target for antidepressant drugs. Among the tested antidepressants (escitalopram, amitriptyline, S-ketamine and R-ketamine), only S-ketamine, and to a lesser extent R-ketamine, induced the expression of most ER stress-responsive genes in astrocytes. Furthermore, cell viability and apoptosis measuring assays showed that (R-)S-ketamine did not affect cell survival under ER stress. Under normal conditions, S-ketamine played the key role in increasing the release of brain-derived neurotrophic factor (BDNF), indicating that the drug has a complex mechanism of action in astrocytes, which may contribute to its therapeutic effects. Our findings are the first to shed light on the relationship between old astrocyte specifically induced substance (OASIS) stabilized by ER stress and (R-)S-ketamine; however, the possible involvement of OASIS in the mechanism of therapeutic ketamine action requires further study.

Ketamine vs midazolam: Mood improvement reduces suicidal ideation in depression

OBJECTIVE

Studies demonstrate rapid antidepressant and anti-suicidal ideation effects of subanesthetic ketamine. The specific subcomponents of depression that are most closely tied to reduction of suicidal ideation with ketamine treatment are less explored.

METHODS

Exploratory, post hoc analysis of data from a randomized clinical trial of ketamine vs midazolam in patients with major depressive disorder (MDD) and clinically significant suicidal ideation examined changes in factor analysis-derived symptom clusters from standard measures of depression (Hamilton Depression Rating Scale, HDRS; Beck Depression Inventory, BDI) and mood disturbance (Profile of Mood States, POMS), and their relationship to severity of suicidal ideation (Beck Scale for Suicidal Ideation; SSI). Ratings obtained before and one day after blinded intravenous infusion were decomposed into component factors or published subscales. Treatment effects on factors/subscales were compared between drugs, correlations with changes in suicidal ideation were tested, and stepwise regression was used to derive predictors of change in SSI.

RESULTS

Factor scores for HDRS Psychic Depression, HDRS Anxiety, BDI Subjective Depression, POMS Depression and POMS Fatigue improved more with ketamine than midazolam. Stepwise regression showed across both drugs that improvement in HDRS Psychic Depression, POMS Depression, and HDRS Anxiety predicted 51.6% of the variance in reduction of suicidal ideation.

LIMITATIONS

Secondary analysis of clinical trial data.

CONCLUSIONS

Ketamine's rapid effects on suicidal ideation appear to be mostly a function of its effects on core mood and anxiety symptoms of MDD, with comparatively little contribution from neurovegetative symptoms with the potential exception of vigor/fatigue.

TRIAL REGISTRATION

Data used in this secondary analysis came from ClinicalTrials.gov identifier: NCT01700829.

[Practical aspects of ketamine treatment-Safety, combination treatment and comorbidities]

BACKGROUND

Although multiple studies and meta-analyses have documented the rapid antidepressive efficacy of ketamine, there are numerous questions regarding the practical use in the clinical routine that are still unanswered.

OBJECTIVE

Based on personal clinical experience, by comparison and supplementation of the current data situation, answers are given to questions regarding the practical use of ketamine for depression that have not yet been satisfactorily clarified.

MATERIAL AND METHODS

The clinical experiences with antidepressive treatment using ketamine over more than 5 years were evaluated with respect to the questions at hand. This was followed by a qualitative comparison of these results with those of a narrative literature search.

RESULTS

A total of 72 patients (unipolar depression n = 53, bipolar depression n = 16, schizoaffective depression n = 3) were included in the analysis of this cohort. A statistically significant reduction of depressive symptoms and suicidal ideation after S-ketamine treatment was found. Of the patients 61% suffered from at least one secondary diagnosis. A dose of 0.5 mg/kg body weight of S‑ketamine at a frequency of three times per week was shown to be effective. The treatment appears to be safe with respect to urotoxic side effects, combination treatment with tranylcypromine and in comorbid posttraumatic stress disorder.

CONCLUSION

Ketamine appears to be a safe and effective option for the treatment of unipolar and bipolar depression.

Looking beyond the opioid receptor: A desperate need for new treatments for opioid use disorder

The mainstay of treatment for opioid use disorder (OUD) is opioid agonist therapy (OAT), which modulates opioid receptors to reduce substance craving and use. OAT maintains dependence on opioids but helps reduce overdose and negative sequelae of substance abuse. Despite increasing availability of OAT, its effectiveness is limited by difficulty in initiating and maintaining patients on treatment. With the worsening opioid epidemic in the United States and rising overdose deaths, a more durable and effective treatment for OUD is necessary. This paper reviews novel treatments being investigated for OUD, including neuromodulatory interventions, psychedelic drugs, and other novel approaches. Neuromodulatory interventions can stimulate the addiction neural circuitry involving the dorsolateral prefrontal cortex and deeper mesolimbic structures to curb craving and reduce use, and multiple clinical trials for interventional treatment for OUD are currently conducted. Similarly, psychedelic agents are being investigated for efficacy in OUD specifically. There is a resurgence of interest in psychedelic agents' therapeutic potential, with evidence of improving mood symptoms and decreased substance use even after just one dose. Exact mechanism of their anti-addictive effect is not fully elucidated, but psychedelic agents do not maintain opioid dependence and some may even be helpful in abating symptoms of withdrawal. Other potential approaches for OUD include targeting different parts of the dopamine-dependent addiction pathway, identifying susceptible genes and modulating gene products, as well as utilizing vaccines as immunotherapy to blunt the addictive effects of substances. Much more clinical data are needed to support efficacy and safety of these therapies in OUD, but these proposed novel treatments look beyond the opioid receptor to offer hope for a more durably effective OUD treatment.

Analysis of recreational psychedelic substance use experiences classified by substance

RATIONALE AND OBJECTIVES

Differences among psychedelic substances regarding their subjective experiences are clinically and scientifically interesting. Quantitative linguistic analysis is a powerful tool to examine such differences. This study compared five psychedelic substance report groups and a non-psychedelic report group on quantitative linguistic markers of psychological states and processes derived from recreational use-based online experience reports.

METHODS

Using 2947 publicly available online reports, we compared Ayahuasca and N,N-dimethyltryptamine (DMT, analyzed together), ketamine, lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), psilocybin (mushroom), and antidepressant drug use experiences. We examined word frequencies related to various psychological states and processes and semantic proximity to psychedelic and mystical experience scales.

RESULTS

Linguistic markers of psychological function indicated distinct effect profiles. For example, MDMA experience reports featured an emotionally intensifying profile accompanied by many cognitive process words and dynamic-personal language. In contrast, Ayahuasca and DMT experience reports involved relatively little emotional language, few cognitive process words, increased analytical thinking-associated language, and the most semantic similarity with psychedelic and mystical experience descriptions. LSD, psilocybin mushroom, and ketamine reports showed only small differences on the emotion-, analytical thinking-, psychedelic, and mystical experience-related language outcomes. Antidepressant reports featured more negative emotional and cognitive process-related words, fewer positive emotional and analytical thinking-related words, and were generally not similar to mystical and psychedelic language.

CONCLUSION

This article addresses an existing research gap regarding the comparison of different psychedelic drugs on linguistic profiles of psychological states, processes, and experiences. The large sample of experience reports involving multiple psychedelic drugs provides valuable information that would otherwise be difficult to obtain. The results could inform experimental research into psychedelic drug effects in healthy populations and clinical trials for psychedelic treatments of psychiatric problems.

Ketamine for the treatment of mental health and substance use disorders: comprehensive systematic review

BACKGROUND

In the past two decades, subanaesthetic doses of ketamine have been demonstrated to have rapid and sustained antidepressant effects, and accumulating research has demonstrated ketamine's therapeutic effects for a range of psychiatric conditions.

AIMS

In light of these findings surrounding ketamine's psychotherapeutic potential, we systematically review the extant evidence on ketamine's effects in treating mental health disorders.

METHOD

The systematic review protocol was registered in PROSPERO (identifier CRD42019130636). Human studies investigating the therapeutic effects of ketamine in the treatment of mental health disorders were included. Because of the extensive research in depression, bipolar disorder and suicidal ideation, only systematic reviews and meta-analyses were included. We searched Medline and PsycINFO on 21 October 2020. Risk-of-bias analysis was assessed with the Cochrane Risk of Bias tools and A Measurement Tool to Assess Systematic Reviews (AMSTAR) Checklist.

RESULTS

We included 83 published reports in the final review: 33 systematic reviews, 29 randomised controlled trials, two randomised trials without placebo, three non-randomised trials with controls, six open-label trials and ten retrospective reviews. The results were presented via narrative synthesis.

CONCLUSIONS

Systematic reviews and meta-analyses provide support for robust, rapid and transient antidepressant and anti-suicidal effects of ketamine. Evidence for other indications is less robust, but suggests similarly positive and short-lived effects. The conclusions should be interpreted with caution because of the high risk of bias of included studies. Optimal dosing, modes of administration and the most effective forms of adjunctive psychotherapeutic support should be examined further.

Ketamine-New Possibilities in the Treatment of Depression: A Narrative Review

The SARS-CoV-2 coronavirus epidemic has led to an increase in the number of people with depression. Symptoms related to the mental sphere (mainly depression and anxiety) may be experienced by one third of the worldwide population. This entails the need for the effective and rapid treatment of depressive episodes. An effective drug seems to be s-ketamine, which was accepted in March 2019 by the Food and Drug Administration (FDA) for the treatment of drug-resistant depression. This drug provides a quick antidepressant effect with maximum effectiveness achieved after 24 h. It also appears to reduce the occurrence of suicidal thoughts. However, research into undesirable effects, especially in groups of people susceptible to psychotic episodes or those who use alcohol or psychoactive substances, is necessary.

Drug Information Needs of Health Care Professionals in Palliative Care: A Retrospective Evaluation of a Palliative Care Drug Information Service

CONTEXT

Drug therapy is an integral part of palliative care but pharmacotherapy can be challenging for health care professionals. Access to information is essential for health care providers to choose the best drug treatment for an individual patient. A drug information service can support health care professionals to obtain appropriate, unbiased information.

OBJECTIVES

To describe the enquiries to a palliative care drug information service. Objectives are to determine the information needs (including off-label use) of different professional groups and areas of care, to identify subject areas and drug substances for which there is a high need for information.

METHODS

Retrospective evaluation of all enquiries to a palliative care drug information service within 24 months from July 2017 to June 2019.

RESULTS

During the study period, 477 enquiries reached the drug information service, mostly from physicians (59%), followed by pharmacists (31%). Ketamin was the most discussed drug (11%), in general enquiries or corresponding replies mostly contained drugs targeting the nervous system, such as analgesics. Application techniques (26%) was the most relevant category, cancer pain (24%) was the most frequently addressed symptom. About half of the enquiries (48%) dealt with off-label us, regarding an application mode outside the license.

CONCLUSION

The information needs on palliative care pharmacotherapy seem to be particularly high among physicians. The demand for information in the area of application technology is particularly apparent and demonstrates a therapeutic gap in terms of availability of suitable preparations as well as necessary information.

Real-world effectiveness of repeated ketamine infusions for treatment resistant depression during the COVID-19 pandemic

Herein we evaluate the impact of COVID-19 restrictions on antidepressant effectiveness of intravenous (IV) ketamine in adults with treatment-resistant depression (TRD). We conducted a case series analysis of adults with TRD (n = 267) who received four ketamine infusions at an outpatient clinic in Ontario, Canada, during COVID-19 restrictions (from March 2020 - February 2021; n = 107), compared to patients who received treatment in the previous year (March 2019 - February 2020; n = 160). Both groups experienced significant and comparable improvements in depressive symptoms, suicidal ideation, and anxiety with repeated ketamine infusions. Effectiveness of IV ketamine was not attenuated during the COVID-19 period.

Leite V, Porto DM, Robis KP, Fidalgo TM, Rocha GA, Diaz AP, Meleiro A, Correa H, Tung TC, Malloy-Diniz L, Quevedo J, da Silva AG. Brazilian Psychiatric Association guidelines for the management of suicidal behavior. Part 2. Screening, intervention, and prevention

This article continues our presentation of the Brazilian Psychiatric Association guidelines for the management of patients with suicidal behavior, with a focus on screening, intervention, postvention, prevention, and promotion. For the development of these guidelines, we conducted a systematic review of the MEDLINE (via PubMed), Cochrane Database of Systematic Reviews, Web of Science, and SciELO databases for research published from 1997 to 2020. Systematic reviews, clinical trials, and cohort/observational studies on screening, intervention, and prevention in suicidal behavior were included. This project involved 14 Brazilian psychiatry professionals and 1 psychologist selected by the Psychiatric Emergencies Committee of the Brazilian Psychiatric Association for their experience and knowledge in psychiatry and psychiatric emergencies. Publications were evaluated according to the 2011 Oxford Center for Evidence-Based Medicine (OCEBM) Levels of Evidence Classification. Eighty-five articles were reviewed (of 5,362 initially collected and 755 abstracts on the drug approach). Forms of screening, intervention, and prevention are presented. The intervention section presents evidence for psychotherapeutic and drug interventions. For the latter, it is important to remember that each medication is effective only for specific groups and should not replace treatment protocols. We maintain our recommendation for the use of universal screening plus intervention. Although the various studies differ in terms of the populations evaluated and several proposals are presented, there is already significant evidence for certain interventions. Suicidal behavior can be analyzed by evidence-based medicine protocols. Currently, the best strategy is to combine several techniques through the Safety Plan. Nevertheless, further research on the topic is needed to elucidate some approaches with particular potential for intervention and prevention. Systematic review registry number: CRD42020206517.

Long-Term Efficacy of Intranasal Esketamine in Treatment-Resistant Major Depression: A Systematic Review

Esketamine (ESK) has been approved as a rapid-acting intranasal treatment for treatment-resistant depression (TRD). Although existing studies have investigated the efficacy of ESK in the 4-week induction phase, our knowledge about long-term ESK efficacy remains poor. The aim of this systematic review was to summarize the available data on long-term ESK efficacy for TRD. A systematic search was performed including articles in English, up to 31 March 2021. The search found 7 relevant studies, involving 1024 adult TRD patients. Continuing treatment with ESK after the 4-week induction phase may be associated with stable efficacy in relapse prevention among TRD patients. Conversely, the long-term antidepressant effectiveness upon discontinuation of ESK might be limited, although data from three studies had a moderate to high risk of bias. Overall, the results on the effectiveness of this compound in the long term are mixed. According to our findings, ESK treatment should be continued following the induction phase to reach a stable efficacy in relapse prevention, while the long-term antidepressant and anti-suicidal effects of ESK after discontinuation are inconsistent. Currently, the level of proof of ESK efficacy in long-term TRD treatment remains low and more RCTs with larger sample sizes and active comparators are needed.

The effect of single administration of intravenous ketamine augmentation on suicidal ideation in treatment-resistant unipolar depression: Results from a randomized double-blind study

This study aimed to assess the effect of a single infusion of intravenous (IV) ketamine on suicidal ideation in patients with treatment-resistant depression (TRD). Patients with TRD were randomized in a double-blind fashion to a single infusion of IV ketamine or IV midazolam placebo. Suicidal ideation was measured using the Montgomery-Asberg Depression Rating Scale (MADRS) suicide item at 3, 5, 7, 14 and 30 days post infusion. Clinically significant suicidal ideation was defined as a MADRS suicide item score ≥2. Forty patients who received IV ketamine and 16 who received IV midazolam had suicide item scores of ≥2 at baseline (IV ketamine group mean 2.90±0.74; IV midazolam group 2.69±0.70). The mean suicide scores of these groups differed significantly from each other on day 30; the IV ketamine group had a lower mean score than controls (2.03±1.59 vs. 3.00±1.41, t-test p = 0.049; Hedges' g 0.71). Among patients with a suicide score of ≥2 at baseline and <2 at day 3, the two groups did not differ significantly on mean scores changes at days 3, 5, 7, 14 or 30. Recurrence of suicidal ideation was extensive in both treatment groups. A single infusion of IV ketamine may reduce suicidal ideation in TRD out to 30 days post infusion, but early anti-suicidal effects appear to diminish rapidly. This post-hoc analysis was not powered to compare different doses of ketamine. A single infusion of IV ketamine might have a role as an adjunct to standard treatments in patients with TRD and suicidal ideation. Trial registration: NCT01920555.

The kynurenine pathway in bipolar disorder: a meta-analysis on the peripheral blood levels of tryptophan and related metabolites

Growing evidence suggests that a dysregulation of the kynurenine pathway (KP) occurs in bipolar disorder (BD). This systematic review and meta-analysis aimed at assessing the possible differences in peripheral blood levels of KP metabolites between individuals with BD and healthy controls. We searched Medline, Embase, and PsycInfo electronic databases for articles indexed up to February 2020. We included any observational study comparing the peripheral blood levels of at least one KP metabolite between adults with BD and healthy controls. Random-effects meta-analyses were carried out generating pooled standardized mean differences (SMDs). Heterogeneity between studies was estimated using the I² index. Meta-regression and sensitivity analyses were conducted. Sixteen studies met inclusion criteria and were included in our study. Meta-analyses showed that individuals with BD have lower peripheral blood levels of tryptophan (SMD = -0.29), kynurenine (SMD = -0.28), kynurenic acid (SMD = -0.30), and xanthurenic acid (SMD = -0.55), along with lower kynurenic acid to kynurenine (SMD = -0.60) and kynurenic acid to quinolinic acid (SMD = -0.37) ratios, than healthy controls. Individuals with a manic episode showed the greatest reductions in tryptophan levels (SMD = -0.51), whereas kynurenic acid levels were more reduced among subjects in a depressive phase (SMD = -0.70). Meta-regression and sensitivity analyses confirmed our results. The findings of the present meta-analysis support the hypothesis of an abnormality of the KP in BD. Considering the partial inconsistency of the findings and the small-to-medium magnitude of the estimated effect sizes, additional research assessing possible mediators or confounders is needed.

Therapeutic Potentials of Ketamine and Esketamine in Obsessive-Compulsive Disorder (OCD), Substance Use Disorders (SUD) and Eating Disorders (ED): A Review of the Current Literature

The obsessive-compulsive spectrum refers to disorders drawn from several diagnostic categories that share core features related to obsessive-compulsive disorder (OCD), such as obsessive thoughts, compulsive behaviors and anxiety. Disorders that include these features can be grouped according to the focus of the symptoms, e.g., bodily preoccupation (i.e., eating disorders, ED) or impulse control (i.e., substance use disorders, SUD), and they exhibit intriguing similarities in phenomenology, etiology, pathophysiology, patient characteristics and clinical outcomes. The non-competitive N-methyl-D-aspartate receptor (NMDAr) antagonist ketamine has been indicated to produce remarkable results in patients with treatment-resistant depression, post-traumatic stress disorder and OCD in dozens of small studies accrued over the past decade, and it appears to be promising in the treatment of SUD and ED. However, despite many small studies, solid evidence for the benefits of its use in the treatment of OCD spectrum and addiction is still lacking. Thus, the aim of this perspective article is to examine the potential for ketamine and esketamine in treating OCD, ED and SUD, which all involve recurring and intrusive thoughts and generate associated compulsive behavior. A comprehensive and updated overview of the literature regarding the pharmacological mechanisms of action of both ketamine and esketamine, as well as their therapeutic advantages over current treatments, are provided in this paper. An electronic search was performed, including all papers published up to April 2021, using the following keywords ("ketamine" or "esketamine") AND ("obsessive" OR "compulsive" OR "OCD" OR "SUD" OR "substance use disorder" OR "addiction" OR "craving" OR "eating" OR "anorexia") NOT review NOT animal NOT "in vitro", on the PubMed, Cochrane Library and Web of Science online databases. The review was conducted in accordance with preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The use and efficacy of ketamine in SUD, ED and OCD is supported by glutamatergic neurotransmission dysregulation, which plays an important role in these conditions. Ketamine's use is increasing, and preliminary data are optimistic. Further studies are needed in order to better clarify the many unknowns related to the use of both ketamine and esketamine in SUD, ED and OCD, and to understand their long-term effectiveness.

Antidepressant Actions of Ketamine: Potential Role of L-Type Calcium Channels

Recently, the United States Food and Drug Administration approved esketamine, the S-enantiomer of ketamine, as a fast-acting therapeutic drug for treatment-resistant depression. Although ketamine is known as an N-methyl-d-aspartate (NMDA) receptor antagonist, the underlying mechanisms of how it elicits an antidepressant effect, specifically at subanesthetic doses, are not clear and remain an advancing field of research interest. On the other hand, high-dose (more than the anesthetic dose) ketamine-induced neurotoxicity in animal models has been reported. There has been progress in understanding the potential pathways involved in ketamine-induced antidepressant effects, some of which include NMDA-receptor antagonism, modulation of voltage-gated calcium channels, and brain-derived neurotrophic factor (BDNF) signaling. Often these pathways have been shown to be linked. Voltage-gated L-type calcium channels have been shown to mediate the rapid-acting antidepressant effects of ketamine, especially involving induction of BDNF synthesis downstream, while BDNF deficiency decreases the expression of L-type calcium channels. This review focuses on the reported studies linking ketamine's rapid-acting antidepressant actions to L-type calcium channels with an objective to present a perspective on the importance of the modulation of intracellular calcium in mediating the effects of subanesthetic (antidepressant) versus high-dose ketamine (anesthetic and potential neurotoxicant), the latter having the ability to reduce intracellular calcium by blocking the calcium-permeable NMDA receptors, which is implicated in potential neurotoxicity.

The acute antisuicidal effects of single-dose intravenous ketamine and intranasal esketamine in individuals with major depression and bipolar disorders: A systematic review and meta-analysis

The efficacy of ketamine in reducing suicidal ideation (SI) has been previously reported. We aimed to evaluate acute anti-SI effects of single-dose ketamine in different formulations/routes of administration by pooling results from randomized controlled trials (RCTs). A systematic search was conducted on Cochrane, Embase, Medline, and PubMed from inception to July 1st, 2020. Studies were selected based on pre-determined eligibility criteria. Effect sizes of different formulations/routes at various time points were computed using random-effects models. With data from nine eligible RCTs (n = 197), the pooled effect size for anti-SI effects at the 24-h time point was 1.035 (N = 6, CI: 0.793 to 1.277, p < 0.001) for intravenous (IV) racemic ketamine and 1.309 (N = 1, CI: 0.857 to 1.761, p < 0.001) for intranasal (IN) esketamine. An additional five RCTs were available for qualitative analysis. RCTs were identified for oral/sublingual ketamine for depression, however, none of these trials reported anti-SI effects preventing quantitative analysis for these routes of delivery. No RCTs for intramuscular (IM) ketamine were identified. The findings suggest that single-dose IV ketamine/IN esketamine is associated with robust reductions in suicidal thoughts at 2-h, 4-h, and 24-h post-intervention. In addition, future studies on IM/oral/sublingual ketamine and comparative studies are warranted to evaluate the anti-SI efficacy of distinct formulations and routes of administration.

Increased use of ketamine for the treatment of depression: Benefits and concerns

Ketamine was initially used as an anesthetic which could induce cognitive impairment and psychomimetic effects. In initial randomized controlled trials (RCTs) that mostly included a small sample size and were investigator-initiated, ketamine reportedly exerted antidepressant effects 1 to 2 h after a single intravenous infusion in patients with major depressive episodes, particularly treatment-resistant depression (TRD). Interest in ketamine was reported in systematic reviews and meta-analyses, however, many were primarily focused on the rapid onset of ketamine effects without equal attention to its safety and tolerability. Furthermore, several meta-analyses were based on many duplicated RCTs. The initial trends emphasized the clinical utility of ketamine as an antidepressant. The development of esketamine nasal spray by a pharmaceutical company led to an RCT with a large sample size and segmented therapeutic strategy, which provided results applicable to patients with TRD in the real-world clinical environment. However, possible effects of ketamine on cognitive function have not yet been investigated in RCTs. In numerous studies, chronic, recreational use of ketamine reportedly substantially impaired cognitive function in most domains. Although results of several human and animal studies indicated the therapeutic use of ketamine for treatment of depression did not induce cognitive impairment, this issue should be further investigated. Based on the current knowledge about ketamine, future antidepressants are expected to be glutamatergic drugs without ketamine-like adverse events (e.g., psychomimetic symptoms and cognitive impairment), but having only ketamine-like therapeutic properties (e.g., rapid antidepressants effects without time lag).

Advances in novel molecular targets for antidepressants

Depression is the most common psychiatric illness affecting numerous people world-wide. The currently available antidepressant treatment presents low response and remission rates. Thus, new effective antidepressants need to be developed or discovered. Aiming to give an overview of novel possible antidepressant drug targets, we summarized the molecular targets of antidepressants and the underlying neurobiology of depression. We have also addressed the multidimensional perspectives on the progress in the psychopharmacological treatment of depression and on the new potential approaches with effective drug discovery.

Ketamine as augmentation for the treatment of major depression and suicidal risk in advanced cancer: Case report

OBJECTIVE

Major depressive disorder (MDD) is common in patients diagnosed with advanced cancer (AC), with a prevalence of 16.5%. It is associated with great disability and worsened quality of life, increased number and intensity of physical symptoms, and lower survival. It is the main factor for the presence of suicidal ideation. Antidepressants show modest efficacy, and response requires several weeks. Ketamine has demonstrated a fast and robust antidepressant effect in subanesthetic doses. This effect may prove useful in patients with AC, MDD, and suicidal risk.

METHOD

We report a case of a patient with advanced cervical cancer who presented with uncontrollable pain, MDD, and a suicide attempt.

RESULT

A 39-year-old woman diagnosed with cervical cancer stage IVB presented to the Emergency Department after a suicide attempt by hanging. Upon evaluation by the palliative care psychiatrist, she reported intense pain, unresponsive to analgesics, and had a history of persistent suicidal ideation. Antidepressant treatment was started (sertraline 50mg/d) after a single dose of ketamine hydrochloride IV (0.5 mg/kg) was administered. Treatment response was measured using the Brief Edinburgh Depression Scale before and after the intervention. The depressive symptoms decreased by 17% on day 1, 39% on day 3, and 72% on day 17.

SIGNIFICANCE OF RESULTS

This case report shows ketamine's efficacy as an augmentation agent alongside conventional antidepressant treatment in patients with AC. Moreover, it shows rapid response in suicidal ideation that has not been achieved with treatment as usual. More clinical trials are needed to support the potential benefit and safety of ketamine in patients with AC, MDD, and persisting suicidal ideation.

Involvement of NMDA receptors containing the GluN2C subunit in the psychotomimetic and antidepressant-like effects of ketamine

Acute ketamine administration evokes rapid and sustained antidepressant effects in treatment-resistant patients. However, ketamine also produces transient perceptual disturbances similarly to those evoked by other non-competitive NMDA-R antagonists like phencyclidine (PCP). Although the brain networks involved in both ketamine actions are not fully understood, PCP and ketamine activate thalamo-cortical networks after NMDA-R blockade in GABAergic neurons of the reticular thalamic nucleus (RtN). Given the involvement of thalamo-cortical networks in processing sensory information, these networks may underlie psychotomimetic action. Since the GluN2C subunit is densely expressed in the thalamus, including the RtN, we examined the dependence of psychotomimetic and antidepressant-like actions of ketamine on the presence of GluN2C subunits, using wild-type and GluN2C knockout (GluN2CKO) mice. Likewise, since few studies have investigated ketamine's effects in females, we used mice of both sexes. GluN2C deletion dramatically reduced stereotyped (circling) behavior induced by ketamine in male and female mice, while the antidepressant-like effect was fully preserved in both genotypes and sexes. Despite ketamine appeared to induce similar effects in both sexes, some neurobiological differences were observed between male and female mice regarding c-fos expression in thalamic nuclei and cerebellum, and glutamate surge in prefrontal cortex. In conclusion, the GluN2C subunit may discriminate between antidepressant-like and psychotomimetic actions of ketamine. Further, the abundant presence of GluN2C subunits in the cerebellum and the improved motor coordination of GluN2CKO mice after ketamine treatment suggest the involvement of cerebellar NMDA-Rs in some behavioral actions of ketamine.

Can Intraoperative Low-Dose R,S-Ketamine Prevent Depressive Symptoms After Surgery? The First Meta-Analysis of Clinical Trials

Background: Postoperative depression is a common complication after surgery that profoundly affects recovery and prognosis. New research indicates that (R,S)-ketamine is a potent antidepressant that exerts a rapid and sustained antidepressive effect. However, there is no consensus on whether intraoperative low-dose (R,S)-ketamine prevents postoperative depression. Objectives: This study aimed to investigate the safety, feasibility, and short-term complications of intraoperative low-dose (R,S)-ketamine in preventing postoperative depressive symptoms. Methods: The Web of Science, Cochrane, PubMed, and CNKI databases were systematically searched (last search February 28, 2020) to identify studies involving ketamine. Sensitivity and metaregression analyses were performed to identify potential confounders. The meta-analysis was performed using Review Manager 5.3. Results: A total of 13 studies (seven in Chinese and six in English) representing 1,148 cases of patients who were treated with (R,S)-ketamine and 874 cases of patients who received other treatments were included in the meta-analysis. Anesthesia duration and blood loss did not significantly differ between the two groups, demonstrating that (R,S)-ketamine was safe (odds ratio,OR: 0.27; 95% CI: -1.14 to 1.68; P = 0.71) for prophylactic treatment of postoperative depression. Blood loss (OR: -1.83; 95% CI: -8.34 to 4.68; P = 0.58), the number of postoperative depressive patients (95% CI: 0.8-1.07; P = 0.08; (R,S)-ketamine: control = 12.9%:15.8%), and postoperative complications (OR: 0.83, 95% CI: 0.44-1.58; P = 0.57; (R,S)-ketamine: control = 19.3%:19.3%) were all similar across groups. Intra-operative low-dose (R,S)-ketamine reduced extubation time (OR: -2.84; 95% CI: -5.48 to -0.21; P = 0.03). Conclusions: The prophylactic anti-depressant effect of (R,S)-ketamine did not significantly differ between the (R,S)-ketamine and control groups in patients undergoing general or spinal anesthesia. However, (R,S)-ketamine use led to a higher incidence of adverse reactions in patients under 40 years of age who underwent a Cesarean section under spinal anesthesia.

Treatments for Self-Injurious Thoughts and Behaviors in Youth: Progress and Challenges

Self-injurious thoughts and behaviors (SITBs) remain a common clinical problem in youth. This article reviews the state of knowledge regarding psychosocial treatments for SITBs in youth. Broadly speaking, psychosocial treatments that incorporate parents/family and that emphasize skills development (including emotion regulation and interpersonal skills) appear to produce the best outcomes. We also describe several challenges to the implementation of evidence-based psychotherapy, as well as potential solutions to these challenges, and provide an illustrative case example. Finally, because even evidence-based psychosocial treatments can take weeks to produce effects, increased attention has been given to biological approaches such as esketamine administration and transcranial direct current stimulation that have potential to yield rapid improvement for acute suicidal ideation, though evidence for the safety and efficacy of these approaches is in the early stages.

Appraising esketamine nasal spray for the management of treatment-resistant depression in adults: Number needed to treat, number needed to harm, and likelihood to be helped or harmed

INTRODUCTION

This post hoc study assessed the evidence-base for esketamine nasal spray for management of treatment-resistant depression (TRD) using number needed to treat (NNT), number needed to harm (NNH), and likelihood to be helped or harmed (LHH).

METHODS

Data sources were four phase III randomized, double-blind studies including two positive studies (acute flexible-dose; maintenance) in patients with TRD. Key efficacy study outcomes: acute response (≥50% decrease from baseline on Montgomery-Asberg Depression Rating Scale [MADRS] total score), acute remission (MADRS scores ≤12). NNT, NNH were calculated for esketamine nasal spray+newly initiated oral antidepressant (esketamine+AD) vs. placebo+AD.

RESULTS

In the pivotal acute flexible-dose study, MADRS response (63.4% vs. 49.5%) and remission (48.2% vs. 30.3%) at 4 weeks resulted in NNT of 8 and 6 for esketamine+AD vs. placebo+AD. NNH values <10 included dissociation (26.1% vs. 3.7%), vertigo (26.1% vs. 2.8%), nausea (26.1% vs. 6.4%), dizziness (20.9% vs. 4.6%), and dysgeusia (24.3% vs. 11.9%). Discontinuation rates due to adverse events (AE) (7.0% vs. 0.9%) yielded NNH=17. LHH comparing MADRS remission vs. discontinuation due to AE was 17 vs. 6. Maintenance use of esketamine+AD demonstrated NNT values<10 for relapse and/or maintenance of remission. In maintenance study, discontinuation due to AE (2.6% vs. 2.1%) yielded NNH=178 (non-significant).

LIMITATIONS

Only dichotomous outcomes were included.

CONCLUSION

NNT<10 for efficacy outcomes suggests potential benefit of esketamine+AD for both acute and maintenance use. LHH was favorable: esketamine+AD was 3 times likely to result in acute remission vs. discontinuations due to AE.

Suicide Risk Assessment and Prevention: Challenges and Opportunities

Despite increased access to mental health care for the previously uninsured and expanding evidence-based treatments for mood, anxiety, psychotic, and substance use disorders, suicide is on the rise in the United States. Since 1999, the age-adjusted suicide rate in the United States has increased 33%, from 10.5 per 100,000 standard population to 14.0. As of yet, there are no clinically available biomarkers, laboratory tests, or imaging to assist in diagnosis or the identification of the suicidal individual. Suicide risk assessment remains a high-stakes component of the psychiatric evaluation and can lead to overly restrictive management in the name of prevention or to inadequate intervention because of poor appreciation of the severity of risk. This article focuses primarily on suicide risk assessment and management as a critical first step to prevention, given the fact that more research is needed to identify precision treatments and effective suicide prevention strategies. Suicide risk assessment provides the clinical psychiatrist with an opportunity for therapeutic engagement with the ultimate goals of relieving suffering and preventing suicide.

Ketamine for depression clinical issues

Major depressive disorder (MDD) is a debilitating illness with significant morbidity and mortality, leading to attempted and completed suicides. It affects interpersonal relationships and also contributes to decreased productivity, causing financial burden to individuals and society. Patients often fail to respond to various antidepressant medication trials resulting in treatment-resistant depression (TRD). Current antidepressant medications work by modulating the monoaminergic systems and takes several weeks to establish a clinical response. Ketamine has been used extensively as an anesthetic agent since the 1970s, and more recent research has shown its rapid and robust effectiveness in TRD the subject of this review. Ketamine is a racemic mixture comprised of two enantiomers (R)-ketamine and (S)-ketamine and acts as an NMDA receptor antagonist. Most research studies have explored its antidepressant and antisuicidal effects by using it as an intravenous infusion or via the intranasal route due to increased bioavailability. Recently an intranasal esketamine spray was approved by the United States Food and Drug Administration (FDA) for TRD as an adjunct to standard antidepressant treatment in a supervised setting. Regarding its safety profile, multiple research studies have established the short-term safety and efficacy of ketamine in TRD. The cardiorespiratory and neuropsychiatric adverse events observed in these studies were mostly transient. However, ketamine is a scheduled agent with abuse potential, making its long-term use challenging and mandating further research.

Ketamine in Bipolar Disorder: A Review

Bipolar disorder (BD) is a psychiatric illness associated with high morbidity, mortality and suicide rate. It has neuroprogressive course and a high rate of treatment resistance. Hence, there is an unquestionable need for new BD treatment strategies. Ketamine appears to have rapid antidepressive and antisuicidal effects. Since most of the available studies concern unipolar depression, here we present a novel insight arguing that ketamine might be a promising treatment for bipolar disorder.

Glutamine and New Pharmacological Targets to Treat Suicidal Ideation

Glutamate is the major excitatory neurotransmitter in the central nervous system, and it is linked with the amino acid glutamine through a metabolic relationship of enzymatic compound interconversion and transportation, also known as the glutamate-glutamine cycle.A growing body of evidence suggests involvement of the glutamatergic neurotransmitter system in suicidal behaviours. The initial evidence comes from the pathophysiology of neuropsychiatric disorders, as disruptions in glutamate neurotransmission have been found underlying pathology in multiple suicide-related psychiatric conditions such as major depressive disorder, schizophrenia, post-traumatic stress disorder, and bipolar disorder.Existing data from experimental animal models and human in vivo studies also demonstrate that glutamate plays a key role in suicide-related personality traits including aggression and impulsive aggression.Further studies on glutamate system dysfunction underlying suicidal behaviours have focused on the different steps of the glutamate-glutamine cycle: an inflammation-mediated reduction of glutamine synthetase activity has been found in depressed suicide attempters, phosphate-activated glutaminase genes are reduced in suicide completers, and gene expression abnormalities in NMDA receptors have also been discovered in suicide victims.Evidence of a role of the glutamate-glutamine cycle in suicidal behaviours unveils new targets for anti-suicide interventions. Lithium's mechanism to reduce the risk of suicide in people with mood disorders may be related to its ability to increase glutamine synthetase, whereas novel NMDA antagonists such as ketamine [or its S(+) enantiomer esketamine] have already demonstrated positive results in reducing suicidal ideation.

Ketamine for suicidal ideation in adults with psychiatric disorders: A systematic review and meta-analysis of treatment trials

OBJECTIVE

Ketamine may reduce suicidal ideation in treatment-resistant depression. But it is not known how quickly this occurs and how long it persists. We undertook a systematic review and meta-analysis to determine the short- and long-term effectiveness of ketamine for suicidality.

METHOD

CENTRAL, EMBASE, Medline, and PsycINFO were searched until 12 December 2018. Randomised controlled trials of ketamine or esketamine reporting data on suicidal ideation, self-harm, attempted or completed suicide in adults diagnosed with any psychiatric disorder were included. Two reviewers independently extracted data, and certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation tool. Standardised mean difference was used for continuous outcomes.

RESULTS

Twenty-five reports from 15 independent trials, with a total of 572 participants diagnosed with predominately affective disorders, were included. The evidence was rated moderate to low. In most trials, ketamine was administered at 0.5 mg/kg via a single intravenous infusion over a 30- to 45-minute period. Only a single trial of intranasal esketamine was identified. At 4 hours post-infusion, treatment with ketamine was associated with a significant reduction in suicidal ideation scores (standardised mean difference = -0.51, 95% confidence interval = [-1.00, -0.03]), which persisted until 72 hours post-infusion (time points between 12 and 24 hours: standardised mean difference = -0.63, 95% confidence interval = [-0.99, -0.26]; between 24 and 72 hours: standardised mean difference = -0.57, 95% confidence interval = [-0.99, -0.14]), but not thereafter. However, there was marked heterogeneity of results. In a single trial of esketamine, marginal effects on suicidal ideation were observed. In terms of actual suicidal behaviour, there were virtually no data on effects of ketamine or esketamine.

CONCLUSION

A single infusion of ketamine may have a short-term (up to 72 hours) beneficial impact on suicidal thoughts. While confirmation of these results in further trials is needed, they suggest possible use of ketamine to treat acute suicidality. Means of sustaining any anti-suicidal effect need to be found.

Suicide Has Many Faces, So Does Ketamine: a Narrative Review on Ketamine's Antisuicidal Actions

PURPOSE OF REVIEW

Suicidal behaviours are a challenge for a medical system and public health, partly due to the current lack of evidence-based, effective, rapid tools for suicidal crisis management. Ketamine and its enantiomer esketamine have raised hopes regarding this issue in the recent years. However, their efficacy in suicidal behaviours and mechanisms for it remain a topic of debate.

RECENT FINDINGS

Subanesthetic ketamine doses rapidly, albeit transiently decrease suicidal ideation, with effects emerging within an hour and persisting up to a week. Current evidence points to various and not necessarily exclusive mechanisms for ketamine's antisuicidal action, including effects on neuroplasticity, inflammation, reward system and pain processing. Ketamine rapidly decreases suicidal ideation, but whether it leads to meaningful clinical outcomes past 1 week is unclear. Multiple putative mechanisms drive ketamine's antisuicidal action. Future studies will have to show long-term ketamine treatment outcomes and further elucidate its mechanisms of action.

Infusing hope into the treatment of suicidality: A review of ketamine's effects on suicidality

PURPOSE OF REVIEW

Given recent increases in rates of suicide and lack of rapid treatments for suicidality, ketamine has been identified as a potential fast-acting anti-suicidal treatment. Our review seeks to describe the effects of ketamine on suicidality, given the growing literature on the use of ketamine in reducing suicidality. We examine open-label studies and randomized controlled trials evaluating treatment of suicidality with ketamine. Furthermore, our manuscript identifies potential mechanisms of ketamine's effects on suicidality.

RECENT FINDINGS

Based on existing RCTs, ketamine appears to have rapid anti-suicidal effects, with most literature studying such effects in timeframes less than one week. Although still in the early stages of research, mechanisms of ketamine include modulation of molecular, inflammatory, neural, cognitive, and behavioral processes.

SUMMARY

Thus, ketamine appears to be a promising treatment for suicidality, but requires larger scale and more robust RCTs to confirm the potential use of this agent in clinical settings.

The Impact of Ayahuasca on Suicidality: Results From a Randomized Controlled Trial

Suicide is a major public health problem. Given increasing suicide rates and limitations surrounding current interventions, there is an urgent need for innovative interventions for suicidality. Although ayahuasca has been shown to target mental health concerns associated with suicidality (i.e., depression and hopelessness), research has not yet explored the impact of ayahuasca on suicidality. Therefore, we conducted secondary analyses of a randomized placebo-controlled trial in which individuals with treatment-resistant depression were administered one dose of ayahuasca (n = 14) or placebo (n = 15). Suicidality was assessed by a trained psychiatrist at baseline, as well as 1 day, 2 days, and 7 days after the intervention. A fixed-effects linear mixed model, as well as between and within-groups Cohen's d effect sizes were used to examine changes in suicidality. Controlling for baseline suicidality, we found a significant effect for time (p < .05). The effect of the intervention (i.e., ayahuasca vs. placebo) trended toward significance (p = .088). At all time points, we found medium between-group effect sizes (i.e., ayahuasca vs. placebo; day 1 Cohen’s d = 0.58; day 2 d = 0.56; day 7 d = 0.67), as well as large within-group (ayahuasca; day 1 Cohen's d = 1.33; day 2 d = 1.42; day 7 d = 1.19) effect sizes, for decreases in suicidality. Conclusions: This research is the first to explore the impact of ayahuasca on suicidality. The findings suggest that ayahuasca may show potential as an intervention for suicidality. We highlight important limitations of the study, potential mechanisms, and future directions for research on ayahuasca as an intervention for suicidality.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT02914769.

Molecular and cellular mechanisms underlying the antidepressant effects of ketamine enantiomers and its metabolites

Although the robust antidepressant effects of the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine in patients with treatment-resistant depression are beyond doubt, the precise molecular and cellular mechanisms underlying its antidepressant effects remain unknown. NMDAR inhibition and the subsequent α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) activation are suggested to play a role in the antidepressant effects of ketamine. Although (R)-ketamine is a less potent NMDAR antagonist than (S)-ketamine, (R)-ketamine has shown more marked and longer-lasting antidepressant-like effects than (S)-ketamine in several animal models of depression. Furthermore, non-ketamine NMDAR antagonists do not exhibit robust ketamine-like antidepressant effects in patients with depression. These findings suggest that mechanisms other than NMDAR inhibition play a key role in the antidepressant effects of ketamine. Duman's group demonstrated that the activation of mammalian target of rapamycin complex 1 (mTORC1) in the medial prefrontal cortex is reportedly involved in the antidepressant effects of ketamine. However, we reported that mTORC1 serves a role in the antidepressant effects of (S)-ketamine, but not of (R)-ketamine, and that extracellular signal-regulated kinase possibly underlie the antidepressant effects of (R)-ketamine. Several lines of evidence have demonstrated that brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine kinase receptor B (TrkB), are crucial in the antidepressant effects of ketamine and its two enantiomers, (R)-ketamine and (S)-ketamine, in rodents. In addition, (2R,6R)-hydroxynormetamine [a metabolite of (R)-ketamine] and (S)-norketamine [a metabolite of (S)-ketamine] have been shown to exhibit antidepressant-like effects on rodents through the BDNF-TrkB cascade. In this review, we discuss recent findings on the molecular and cellular mechanisms underlying the antidepressant effects of enantiomers of ketamine and its metabolites. It may be time to reconsider the hypothesis of NMDAR inhibition and the subsequent AMPAR activation in the antidepressant effects of ketamine.

Research on the pathophysiology, treatment, and prevention of suicide: practical and ethical issues

BACKGROUND

Despite decades of research, the rate of death from suicide is rising in the United States. Suicide is a complex and multifactorial phenomenon and, to date, no validated biomarkers that predict suicidal behavior have been identified. Only one FDA-approved drug to prevent suicide exists, and it is approved only for patients with schizophrenia. Although anti-suicide psychotherapeutic techniques exist, treatment takes time, and only preliminary data exist for rapid-acting therapies.

DISCUSSION

While more research into suicidal ideation and acute suicidal behavior is clearly needed, this research is fraught with both practical and ethical concerns. As a result, many investigators and bioethicists have called for restrictions on the types of research that individuals with suicidal behavior can participate in, despite the fact that the available empirical evidence suggests that this research can be done safely. This manuscript presents background information on the phenomenology of suicide, discusses the current state of treatment and prevention strategies, and reviews the practical and ethical issues surrounding suicide research in the context of available empirical data. Currently, the causes of suicide are poorly understood, in part due to the fact that very few studies have investigated the acute suicidal crisis. Although some biomarkers for predicting risk have been developed, none have been sufficiently validated. The most successful current interventions involve means restriction. However, while numerous hurdles face researchers, these are not insurmountable. The available evidence suggests that research into suicide can be conducted both safely and ethically.

Suicide Prevention Strategies for General Hospital and Psychiatric Inpatients: A Narrative Review

BACKGROUND

In-patient (IP) suicides contribute a small but significant proportion of overall suicides. Despite this, suicide prevention strategies focusing on the general hospital IP population remain relatively underresearched. This paper is intended to provide an overview of various proposed suicide prevention approaches in the general hospital, including psychiatric IP, settings, and their evidence base.

METHODOLOGY

Electronic searches of MEDLINE through PubMed, ScienceDirect, and Google Scholar databases were performed to identify potentially relevant articles from inception till January 2019. The generated abstracts were systematically screened for their eligibility to be included in the review. Included articles were grouped under five broad themes: environmental modification, staff education, pharmacotherapy, psychotherapy, and brain stimulation. Data extraction was done using a structured proforma.

RESULTS

Environmental modifications and educating the health care professionals appear to be the most promising strategies to reduce suicide-related mortality among IPs. Among pharmacological methods, ketamine has shown initial promise in reducing suicidal ideations. Follow-up data are lacking for most of the described methods. Limited but positive evidence exists for cognitive therapies focusing on the immediate postadmission period and brain stimulation techniques, and it warrants further replication.

CONCLUSION

There is a striking paucity of original research on IP suicide prevention. Given the ethical and methodological issues in carrying out studies with IP suicide as the primary outcome, there is a need to focus on intermediate suicide outcome measures, such as knowledge, attitude, and skills among staff handlers of suicidal patients.

The role of NMDA receptor in neurobiology and treatment of major depressive disorder: Evidence from translational research

There is accumulating evidence demonstrating that dysfunction of glutamatergic neurotransmission, particularly via N-methyl-d-aspartate (NMDA) receptors, is involved in the pathophysiology of major depressive disorder (MDD). Several studies have revealed an altered expression of NMDA receptor subtypes and impaired NMDA receptor-mediated intracellular signaling pathways in brain circuits of patients with MDD. Clinical studies have demonstrated that NMDA receptor antagonists, particularly ketamine, have rapid antidepressant effects in treatment-resistant depression, however, neurobiological mechanisms are not completely understood. Growing body of evidence suggest that signal transduction pathways involved in synaptic plasticity play critical role in molecular mechanisms underlying rapidly acting antidepressant properties of ketamine and other NMDAR antagonists in MDD. Discovering the molecular mechanisms underlying the unique antidepressant actions of ketamine will facilitate the development of novel fast acting antidepressants which lack undesirable effects of ketamine. This review provides a critical examination of the NMDA receptor involvement in the neurobiology of MDD including analyses of alterations in NMDA receptor subtypes and their interactive signaling cascades revealed by postmortem studies. Furthermore, to elucidate mechanisms underlying rapid-acting antidepressant properties of NMDA receptor antagonists we discussed their effects on the neuroplasticity, mostly based on signaling systems involved in synaptic plasticity of mood-related neurocircuitries.